A suitable 'do nothing' lambda expression in python?

Question

I sometimes find myself wanting to make placeholder \'do nothing\' lambda expressions, similar to saying:

def do_nothing(*args):
    pass

B

Answer 1

Sometimes lambda functions are used for data transformation, and in that case 'do nothing' means to return the input, i.e.

lambda x: x

To return none you can write

lambda x: None